Injection apparatuses are known as apparatuses for molding a desired product by injecting a molding material into a mold and filling the mold with the molding material. See Patent Document 1, for example. The injection apparatus of this type generally operates in three steps: a low-speed step, a high-speed step and a pressure-increasing step; operates the piston of an injection cylinder at a desired speed in the respective steps; and also operates to impart a desired pressure to the molding material in a mold.